1. Field of Invention
This invention relates to reciprocal latching ferrite phase shifters, and more particularly to monolithic reciprocal latching ferrite phase shifters.
Description of the Prior Art
As is well known in the state of the art, ferrite phase shifters find their most extensive use in the field of electronically scanned, phased array antenna systems due to their inherent ability to handle high peak and average power levels. Systems which employ separate electronically scanned phased array antennas for the transmit and receive functions, such as a bistatic radar, require a phase shift of the wave in one direction only, and therefore non-reciprocal ferrite phase shifters may be successfully employed. However, more typically a single electronically scanned antenna is used for both the transmit and receive functions as in a monostatic radar system. The use of nonreciprocal ferrite phase shifters in such a monostatic radar system would require the phase shifters to be reset between transmission and reception, causing problems in short range and high PRF systems. Therefore, reciprocal ferrite phase shifters are more desirable, and reciprocal latching ferrite phase shifters have been developed in the prior art such as that described by C. R. Boyd in a paper entitled A Dual Mode Latching Reciprocal Ferrite Phase Shifter, published in IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-18, No. 12, Dec., 1970, pages 1119-1124.
Some prior art phase shifters have consisted of individual component parts which are mechanically joined through bonding or mechanically mounting, resulting in some instances to physically cumbersome devices. Still other prior art phase shifters have involved intricate construction steps in fabricating the individual components to provide the individual functional characteristics, which result in high manufacturing costs. These two features, large size and high cost, are of critical importance in designing an electronically scanned phased array antenna system which typically comprises 1700 elements in the array, and where each wave conducting element must be provided with its own individual phase shifter.